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    <title>Document</title>
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<body>
    <script>
        /*
            es5只有全局作用域和函数作用域，没有块级作用域,所以在es6中使用let来声明变量
        */
        var name = "John";
        while (true) {
            var name = "Pete";
            console.log(name);  //pete
            break
        }
        console.log(name);  //pete

    </script>
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